Microsoft has the right idea by implementing Smart Cards that not only allow their employees to access their computing resources, but their physical campus as well. But why stop there? Smart Cards are essentially cryptographic tokens that not only enable "something you have" security, but strong authentication using PKC (Public Key Cryptography). A traditional metal key provides "something you have", but it can't provide PKC. PKC is used in most modern Cryptography systems like SSL, S/MIME, or PGP just to name a few. Essentially, it's the strongest form of authentication ever invented and it can also enable strong encryption by providing a secure key exchange.

So why stop at access to the building and computer systems, how about replacing all of the following applications with a single standardized cryptographic token with an integrated finger print reader and/or numeric keypad for good measure.

Credit Card and ATM Card replacement

Car key replacement

House key replacement

Building badge replacement

Computer and Network login

Wireless Access token

VPN Access token

Un-forgeable passport with Digitally Signed Photo

Un-forgeable driver's license with Digitally Signed Photo

Un-forgeable Social Security Number with Digitally Signed Photo

Now imagine that you could just carry a single token to do all that! Maybe on a key chain, maybe built in to a watch, or maybe something else or whatever your choice. I would like that very much.